The number of Americans living with HIV is currently 1.2 million, but only about one in four Americans have their infection under control. It’s hard to trace why there is such a gap in treatment, but in part, it’s because one in five Americans living with the disease don’t know they have it. Of those who do know they have it, only half are receiving ongoing medical treatment.

As part of our ongoing inequality series, we’re looking at the differences in diagnosis and treatment of HIV/AIDS in different populations. Black males and men who have sex with men (MSM) have disproportionately high rates of HIV. Black males are about six and a half times more likely to contract HIV than white males. Among African-Americans living in cities, almost a third of black MSM are HIV positive. The inequality of HIV is even more drastic among MSM, where the rate of diagnosis is 44 times that of other men.

The inequalities exist on a global level too. Sub-Saharan Africa accounts for 12 percent of the global population, but 68 percent of people living with HIV live there. Unlike the U.S., where men are at higher risk, women account for 59 percent of those with HIV in Sub-Saharan Africa.

What accounts for the inequalities in rates and treatment of HIV among different demographics domestically and internationally? How do you see inequality at work among the populations suffering from HIV/AIDS?